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The untold – and terrifying – story behind the earthquake that devastated Nepal on a Saturday morning in 2015 begins with something that sounds quite benign. It’s the ebb and flow of rainwater in the great river deltas of India and Bangladesh, and the pressure that puts on the grinding plates that make up the surface of the planet. Recently discovered, that causal factor is seen by a growing body of scientists as further proof that climate change can affect the underlying structure of the Earth.

Because of this understanding, a series of life-threatening "extreme geological events" – earthquakes, volcanoes and tsunamis – is predicted by a group of eminent geologists and geophysicists including University College London’s Bill McGuire, professor emeritus of Geophysical and Climate Hazards. "Climate change may play a critical role in triggering certain faults in certain places where they could kill a hell of a lot of people," says Professor McGuire. Some of his colleagues suspect the process may already have started.

It sounds like a pitch for a Hollywood apocalypse-fest – indeed the movie 2012 featured the Earth’s crust collapsing after a rapid heating of the Earth’s core. The mechanism here is rather more mundane, though potentially no less devastating. Evidence from the end of the last Ice Age has already shown that the planet’s uneasy web of seismic faults – cracks in the crust like the one that runs along the Himalayas – are very sensitive to the small pressure changes brought by change in the climate. And a sensitive volcano or seismic faultline is a very dangerous one. The disappearing ice, sea-level rise and floods already forecast for the 21st century are inevitable as the earth warms and weather patterns change – and they will shift the weight on the planet.

Professor McGuire calls this process “waking the giant” – something that can be done with just a few gigatonnes of water in the right – or wrong – place.